A mechanical model was established for modeⅡinterfacial crack static growing along an elastic_elastic power law creeping bimaterial interface. For two kinds of boundary conditions on crack faces, traction free and fr...A mechanical model was established for modeⅡinterfacial crack static growing along an elastic_elastic power law creeping bimaterial interface. For two kinds of boundary conditions on crack faces, traction free and frictional contact, asymptotic solutions of the stress and strain near tip_crack were given. Results derived indicate that the stress and strain have the same singularity, there is not the oscillatory singularity in the field; the creep power_hardening index n and the ratio of Young's module notably influence the crack_tip field in region of elastic power law creeping material and n only influences distribution of stresses and strains in region of elastic material. When n is bigger, the creeping deformation is dominant and stress fields become steady,which does not change with n. Poisson's ratio does not affect the distributing of the crack_tip field.展开更多
A mechanical model is established for mode II interfacial crack static growing along an elastic-elastic power law creeping bimaterial interface. For frictional contact of boundary conditions on crack faces, asymptotic...A mechanical model is established for mode II interfacial crack static growing along an elastic-elastic power law creeping bimaterial interface. For frictional contact of boundary conditions on crack faces, asymptotic solutions of the stresses and strains of near tip-crack are got. It was shown that in stable creep growing phase, elastic deformation and viscous deformation are equally dominant in the near-tip field, the stress and strain have the same singularity and there is not the oscillatory singularity the field. Through numerical calculation , it is shown that the frictional coefficient η notably influence the crack-tip field.展开更多
Based on the principles of virtual work for continuum medium,the element free Galerkin method to simulate the numerical calculations of steady-state creep was used and the discrete equation was derived in meshlss meth...Based on the principles of virtual work for continuum medium,the element free Galerkin method to simulate the numerical calculations of steady-state creep was used and the discrete equation was derived in meshlss method for steady-state creep.The es- sential boundary conditions and volume incompressible conditions can be realized by em- ploying the penalty parameters,so the symmetric positive definite system stiffness matrix can be yielded.Results of numerical cases show that element free Galerkin method,with its high accuracy,is much more convenient to deal with the pre-process and post-process, the results by meshless method is in good agreement with the exact solution data.展开更多
This document uses previous results (which we call the first stage), for the development of a computer model based on finite elements under the FEAP programmer, to carry out a structural analysis of a pipeline. For th...This document uses previous results (which we call the first stage), for the development of a computer model based on finite elements under the FEAP programmer, to carry out a structural analysis of a pipeline. For this purpose, we used environmental variables that we believe influence the failure of buried pipelines such as the internal pressure of fluid, the type of support used, the temperature at which the pipelines work, the type of soil and the stiffness of the soil acting on it. Once the model was finalized, analyses were made with each of the variables separately and combined to observe the behavior of the pipeline, finding the most unfavorable case that indicates the main causes that led to its failure.展开更多
An asymptotic analysis is made on problems with a steady-state crack growth cou- pled with a creep law model under tensile loads. Asymptotic equations of crack tip fields in creep materials are derived and solved nume...An asymptotic analysis is made on problems with a steady-state crack growth cou- pled with a creep law model under tensile loads. Asymptotic equations of crack tip fields in creep materials are derived and solved numerically under small scale conditions. Stress and strain func- tions are adopted under a polar coordinate system. The governing equations of asymptotic fields are obtained by inserting the stress field and strain field into the material law. The crack growth rate rather than fracture criterion plays an important role in the crack tip fields of materials with creep behavior.展开更多
基金theNaturalScienceFoundationofHeilongjiangProvince China (A0 0 9)
文摘A mechanical model was established for modeⅡinterfacial crack static growing along an elastic_elastic power law creeping bimaterial interface. For two kinds of boundary conditions on crack faces, traction free and frictional contact, asymptotic solutions of the stress and strain near tip_crack were given. Results derived indicate that the stress and strain have the same singularity, there is not the oscillatory singularity in the field; the creep power_hardening index n and the ratio of Young's module notably influence the crack_tip field in region of elastic power law creeping material and n only influences distribution of stresses and strains in region of elastic material. When n is bigger, the creeping deformation is dominant and stress fields become steady,which does not change with n. Poisson's ratio does not affect the distributing of the crack_tip field.
基金the Natural Science Foundation of Heilongjiang Province(A009).
文摘A mechanical model is established for mode II interfacial crack static growing along an elastic-elastic power law creeping bimaterial interface. For frictional contact of boundary conditions on crack faces, asymptotic solutions of the stresses and strains of near tip-crack are got. It was shown that in stable creep growing phase, elastic deformation and viscous deformation are equally dominant in the near-tip field, the stress and strain have the same singularity and there is not the oscillatory singularity the field. Through numerical calculation , it is shown that the frictional coefficient η notably influence the crack-tip field.
基金the Youth Science Foundation of Anhui Province(08040106831)Key Projects on College Natural Science Research of Anhui Province(KJ2008A125)
文摘Based on the principles of virtual work for continuum medium,the element free Galerkin method to simulate the numerical calculations of steady-state creep was used and the discrete equation was derived in meshlss method for steady-state creep.The es- sential boundary conditions and volume incompressible conditions can be realized by em- ploying the penalty parameters,so the symmetric positive definite system stiffness matrix can be yielded.Results of numerical cases show that element free Galerkin method,with its high accuracy,is much more convenient to deal with the pre-process and post-process, the results by meshless method is in good agreement with the exact solution data.
文摘This document uses previous results (which we call the first stage), for the development of a computer model based on finite elements under the FEAP programmer, to carry out a structural analysis of a pipeline. For this purpose, we used environmental variables that we believe influence the failure of buried pipelines such as the internal pressure of fluid, the type of support used, the temperature at which the pipelines work, the type of soil and the stiffness of the soil acting on it. Once the model was finalized, analyses were made with each of the variables separately and combined to observe the behavior of the pipeline, finding the most unfavorable case that indicates the main causes that led to its failure.
基金supported by the National Natural Science Foundation of China(Nos.11272096 and 11472086)the Research Fund for the Doctoral Program of Higher Education of China(No.20112304110015)
文摘An asymptotic analysis is made on problems with a steady-state crack growth cou- pled with a creep law model under tensile loads. Asymptotic equations of crack tip fields in creep materials are derived and solved numerically under small scale conditions. Stress and strain func- tions are adopted under a polar coordinate system. The governing equations of asymptotic fields are obtained by inserting the stress field and strain field into the material law. The crack growth rate rather than fracture criterion plays an important role in the crack tip fields of materials with creep behavior.
